What I would really love as a feature for this mod is the ability to only allow survival flight for players if they are within beacon range and the beacon is of a certain block (for example: only grant flight if the base is made of netherite blocks). If you could add this feature it would be much appreciated!

I would greatly appreciate this. I use 1.20.1 (if this is what you mean by version). Also, do you have a place I can donate to you? I'm a college student and I also have no idea how much effort doing something like this requires on your part but I'd like to compensate what I am able if you are alright with going through and making this.

If you really really want this i'm fine making a one off version that has it but it's not getting released outside of this gh issue and i will not port it.
I'll also probably just rip the code from better beacons so it'll be incompatible with it.
so if you're fine with that just tell me the version

but i'm not adding it to the main version just because i really don't want to maintain that feature

there i've transfered the repo with the mod.
make it public if you like.
donation wise the only thing i take is amazon.de gift cards, you could email em to me i guess? (mostly use em to donate to others) but it's fine.
effort wise it was thrown together in about an hour.... the appended vid is litterally all the testing i did sooo +1minute of testing.
hope it's not too jank, best of luck with it.

EDIT: forgot to mention what the mod does it adds: nick_beacon, nick_beacon_delayed, nick_beacon_level and nick_beacon_level_delayed, you can easily enough rename the conditions by changing them in src/main/java/tf/ssf/sfort/nicks_beacon_block_fscript_addon/FlightScript.java

and since it's a fscript addon it'll also work for Fabrication (untill mojang updates it outa existance at least ;p)

you can just put nick_beacon:netherite_block inside .minecraft/config/SurvivalFlight/creative_flight.script
in case you want more conditions / are just curious how it works, you can look at #9

i've also edited the previous message with the other conditions available, dunno if you get an email for edits